Republican state Sen. Mimi Walters has a 94 percent lifetime rating with California’s anti-tax group, but that might not be enough for her to avoid a anti-tax primary challenger as she runs for Congress.

Walters is the early front-runner to replace retiring Rep. John Campbell (click here for Roll Call’s interview with her). And by every traditional measure, she should win the seat easily. But one vote for a Democrat-sponsored tax extension (SB 11) is being viewed as ideological treason by some anti-tax conservatives.